In the prior art, bottom unloader augers, with means provided for central discharge through the bottom, of silage, is well known. An example of a silo center discharge, and an auger adaptable for use therewith, at the bottom of a silo, is present in my prior U.S. Pat. No. 4,057,151. The center discharge openings generally have covers, and these may be constructed like the teachings of my U.S. Pat. No. 4,057,153. In bottom unloaders, as the auger moves around the bottom of the silo (which auger can be constructed like that set forth in my U.S. Pat. No. 4,095,703), silage is discharged toward the bottom opening, and may later be conveyed outwardly from the silo, by other means. Except when the silage is being discharged through the bottom opening, the cover for the bottom opening is generally kept shut, in order to minimize oxygen inflow into the system.
This is because, the inflow of oxygen into the system will cause a certain amount of oxidation of the silage therein, whether it be hay, grain, or any other agricultural product. Each oxidation thereby effects the loss of a certain amount of silage, and it is preferably avoided.
When silos are filled from an outside pipe, the silage may be blown into the top of the silo toward the center thereof, and preferably toward a central deflector, in an arrangement similar to that shown in my U.S. Pat. No. 4,052,108. It has been found that, when the silo is being filled, because of the volume of material and air that is being driven into the top of the silo through the fill pipe, provision must be made for the displacement of air (or gas, including air) from the top of the silo. To this end, an openable lid at the top of the silo is generally used to facilitate venting and such displacement, when the silo is being filled. The lid is generally promptly closed after the filling takes place. As the silage in the silo becomes heated, often from the action of the sun, or even if not heated from the sun, if it becomes warm because of oxidation, it often happens that a higher pressure becomes present in the silo, above the level of the silage therein. This may in part be due to the tendency of heat to rise, but in any event, generally effects a higher pressure zone at the top of the silo, above the silage. When this happens, if the cover on the bottom of the silo center discharge is opened, the pressure differential between the top and bottom of the silo may cause air containing the customary amounts of oxygen, to be drawn into the bottom of the silo, in a rapid sucking action.
The present invention is directed toward eliminating, or substantially eliminating the pressure differential through the silage, from top to bottom, by providing a duct from the top to the bottom, that communicates the zone at about the bottom opening of the silo, with the zone inside the silo above the silage, and that preferably additionally communicates with gas bags reserved for preventing loss of the silo gases having desirable qualities such as reduced oxygen content, higher heat, greater humidity, etc. Accordingly, a conduit provides connection between the top and the bottom of the silo, as well as communication with silo gas bags. This is the essence of this invention, particularly, the utilization of the silo fill pipe, and a vent connected thereto at its bottom, that in turn is connected to the gas bags and the fill opening. Additionally, the bottom of the fill pipe has a telescopic member for adaption to fill equipment, and additionally, is sealed by means of an openable closure at its lower end, located below the communication of the vent with the fill pipe, for acting as a moisture trap when the closure is closed. Furthermore, the upper end of the fill pipe extends into the silo beyond the location of the roof vent. This latter feature has been found to effect less carrying of silage and dust out of the upper end of the silo during the filling operation, as has been experienced with vent openings conventionally placed in the roofs, and with fill pipes that terminate at the silo wall, rather than extending inwardly past the vent opening.
In the constructions of silos, it has often been found that silage dust and rainwater effect a staining of the silo walls, in that rainwater picks up accumulated dust on the roof, and runs downwardly therefrom staining the wall of the silo.
The present invention applies a drip member around the upper edge of the silo, that is generally frusto-conical in configuration, terminating at its lower end in a drop edge, whereby rainwater, melting snow and the like carrying particles may be dropped from the upper end of the silo, at a location located six inches, more or less, from the silo wall, so that they will not run down the silo from its upper end staining the same. Additionally, by constructing the drip member as two surfaces having a common juncture, one said surface may be generally cylindrical and upstanding, and may be bolted or otherwise carried to an imbedded reinforcing member in the concrete, and thereby allow its use as a peripheral form for the poured concrete roof, which form remains in place, after hardening of the concrete, and serves to hold the outwardly extending peripheral sheet previously described that provides the discussed drip edge.